Electron beam generator and emission cathode

ABSTRACT

An electron beam generator having an electron emission cathode adopted to be rapidly mounted to an installation, has an electronically insulating support body that is clamped on one side to a metal contact body having a large surface area. At the other side of the electrically insulating support body, a quick release device is arranged in order to rapidly mount and dismount the generator to an installation.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to an electron beam generator having aheated electron emission cathode, to an electron beam evaporator devicehaving such a generator, and to a vacuum treatment installation havingan electron beam evaporator and an electron beam generator.

DESCRIPTION OF THE PRIOR ART

An electron beam generator is used in vacuum vaporization installationsfor the generation of an electron beam which, after having beengenerated, is deflected by electron-optical means onto a crucible inorder to vaporize material placed in the crucible. The generatorincludes an electron emission cathode which is heated either directly byjoulean heat or indirectly e.g. in that it is mounted in the immediatearea of a heating member. In both cases a negative high voltagepotential is usually applied to the electron emission cathode and e.g. aground potential is applied to an anode located directly over thecathode. Similarly, the ground potential is applied to parts of theinstallation onto which such a generator is mounted. Thus, high voltagesexist over such an electron beam generator such that a correspondinginsulation of part of the installation between the mounting parts of thecathode and the mounting parts for the generator, must be used.

A second demand which must be met for such generators is that theelectron emission cathode must be extremely precisely positionedrelative to the part of the installation to which it is mounted, suchthat electrons which are emitted from the cathode, after passing theanode of the generator, enter subsequent electron-optical units in areproducibly precise fashion. This must also take the high temperaturegradient produced at the generator into consideration.

SUMMARY OF THE INVENTION

It is a general object of the invention to provide an electron beamgenerator which has an extremely simple and rugged design and at whichthe reproducibly precise mounting of the cathode and of otherelectron-optical parts is guaranteed in a simple and reliable fashion.

A further object is to provide an electron beam generator which has anelectrically insulating supporting body which, on one side, is adaptedfor mounting the generator in an installation, and on the other side, isadapted for receipt of the electron emission cathode. The supportingbody includes mechanical position reference abutment surfaces for atleast the electron emission cathode and further electron-optical partsof the generator, such that an exchanging of cathodes is made simple andreproducible, and also a mounting or demounting of the entire generator,e.g., for cleaning purposes, is simple and reproducibly precise.

Still a further object is to provide a generator where clearly definedand reproducible temperature conditions are provided and where the useof the supporting body as a mechanical reference allows for differingthermal expansions of the insulators and the metal parts, without anyinfluence on the electron-optical conditions.

A further object is to provide a generator in which a supporting body ofAl₂ O₃ is used.

Still a further object is to provide a generator having a structurallysimple design so that a defined reproducible heat conduction isguaranteed between the part of the supporting body at the cathode andmetal parts of the installation to which the generator is mounted.

Yet a further object is to provide a generator wherein the supportingbody is clamped at one side to a metal contact body over a large surfacearea so that the necessary heat conducting conditions between theinsulating supporting body and the metal contact body, are met.

A further object is to provide an electron beam generator which can bemounted and demounted, in a simple fashion, to a complete vaporizerinstallation including for instance, electron-optics and crucibles, sothat if it is necessary to interrupt a vapor deposition process, forexample, when the electron emission cathode has been consumed, this canbe done quickly.

Yet a further object is to provide a generator which has at least onequick release device for a rapid mounting of the generator to thesupporting body.

Still a further object is to provide a generator in which the quickrelease device includes at least one projecting bolt having a radialconical bore.

A further object is to provide a quick release device for connecting apart of an installation to an electron beam generator, which partincludes a receiving bore for a bolt having a radial conical bore. Aradial clamping screw including a conical tip is adapted to be driveninto the bore. The axis of the screw is offset relative to the axis ofthe bore in the bolt when the bolt is inserted and prior to driving thescrew in, so as to clamp the generator to the part when the screw isdriven in, via the conical bore.

Yet a further object is to provide a quick release device which allowsan electron beam generator to be clamped, via a quick release device, toa part of the installation so that the generator is in an unequivocallydefined position, and to guarantee a reproducible heat conducting effectby means of this clamping, between the generator and the mentioned partof the installation, to which the generator is clamped.

A further object is to provide a generator in which the electronemission cathode is a cathode which is heated directly by joulean heator heated indirectly, preferably a cathode assembled as a structuralunit, having heating members.

Yet a further object is to provide a generator having two metal cathodeconnection supporting blocks arranged to locate and fix the cathodedespite alternating high thermal loading.

A still further object is to provide a generator in which the cathode ismounted relative to an emission surface in a point contact manner suchthat it can thermally expand freely without distortion. In the preferredembodiment, according to which the cathode is designed as a cathodeheated by joulean heat or as an indirectly heated cathode, twosubstantially parallel supporting terminals, preferably also forreceiving the heating current, are provided and project on the same siderelative to the cathode emission surface. The cathode is supported andheld mechanically by these two terminals to allow free thermal expansionas set forth above, and preferably also to receive electric power forthe cathode.

A further object is to provide a generator in which each of the cathodeterminal blocks includes a locating device for one of the cathodeterminals.

A still further object is to provide a generator which guarantees afaultless exchange of cathodes that must all be mounted in only onesingle, specific position and where the cathode terminals are designeddifferently at the cathode side and in the same way the locating devicesare designed differently at the generator side such that a respectivecathode terminal can be inserted merely into one of the locating devicessuch that a faultless inserting of a cathode is guaranteed. This insuresthat a cathode can be mounted only in one single predeterminatedposition so that it is impossible to mount the cathode with the wrongsurface facing the direction of emission.

A further object is to provide a generator in which not only asurface-wise correct mounting of the cathode as set forth above is madepossible but also a mounting in a precisely set position and where anabutment device is located at least at one of the locating devices suchthat the emission cathode must be brought into the abutting position andthen must be fastened there.

It has been mentioned earlier that high voltage values are usuallypresent at such electron beam generators between the cathode and partsof the installation to which the generator is mounted. Accordingly, itis of the utmost importance that the insulation between the cathode andthe mentioned parts of the installation, have permanent high surfaceresistance. This must be insured despite the great many applications forsuch generators. It may not be self-evident, for example, when thinkingof vacuum vapor deposition installations, that often conductive materialis vaporized from the crucible or pot, which quite obviously can bedeposited on the insulating parts of the beam generator. The cathode isalso vaporized during its operation in that it is exposed to abombardment of ions. Thus a second source of material that can impairthe insulation stems from the cathode at the generator. The twomentioned factors which impair the insulation have in common thatvaporized conductive material comes in a quite predominant amountregarding the generator from that side against which the emissionsurface of the cathode is facing, or from the side toward which theelectron beam is generated.

Accordingly, it is a further object of the invention to protect thesurface insulation from impairment due to vaporized cathode material andprocess vapor in that the supporting body is covered by overhangs and apreferably circular recess for increasing the length of the path ofcreeping current between the two sides of the supporting body is alsoprovided.

A further object is to provide a generator having cathode supportingblocks as set forth above which must be separated from each other forheating current supply to the cathodes, i.e. where a gap is providedbetween the parts and wherein the impairment of the surface insulationis prevented in that the cathode supporting blocks overhang thesupporting body and are designed to extend in a complementary formwithout contacting each other so that the supporting body is completelyconcealed by the cathode supporting blocks from the direction of theother side of the supporting body, i.e. from that side on which the beamis generated.

A further object is to provide a generator in which only the cathodesupporting blocks are acted upon by or exposed to vapor from the cathodeor the production process which, as long as their electric separation issecured, remains without any influence regarding the function of thegenerator.

In case of directly or indirectly heated electron emission cathodes, ahigh heating current which can amount to several amps must flow throughthe cathode or heating device. Such a current generates a considerablemagnetic field which can strongly influence the emission characteristicsof the cathode and also the propagation of the electrons. When it istaken into consideration that there is an advantage for directly heatedelectron emission cathodes and also for indirectly heated cathodes to bedesigned so that their structures are closed in themselves since theperformance of the emission can be adjusted quite simply by changes inthe heating current, it becomes obvious that this magnetic field at highcurrents cannot be neglected. In the case of an AC-power supply, or alsomerely upon changes in a DC-heating current including an AC-magneticfield, just as for the DC-portion of an AC-supply, the magnetic fieldscan be extremely disturbing regarding the desired emission andpropagation characteristics of the generator. In order to counteractthis situation it is an object of the invention to provide a generatorstructured such that power supply conductors at the generator for acathode heating current intersect an emission surface of the cathode, ata spatial plane defined by this surface, specifically a planar plane atan as large as possible distance, i.e. to lead the power supply lines orbars to the heated emission cathode such that when viewing the emissionsurface of the cathode, these power supply lines initially pass througha plane defined by the emission surface initially at a large distancefrom this emission surface. As long as the power supply lines arelocated below the plane defined by the emission surface it is possibleto shunt the magnetic fields generated in these power supply lineslargely by metal shielding or control electrodes.

A still further object is to provide a generator wherein the supportingbody forms a structure in the shape of a substantially parallelepipedblock and in that the emission surface of the cathode is locatedsubstantially in one of the corners of the surfaces of the block, andwherein heating power supply lines for the cathode are located at a sidesurface of the block which does not form the mentioned corner, i.e. whenthe emission surface of the cathode is located substantially at the onecorner of one of the surfaces of the parallelepiped block where thecurrent supply lines for this cathode are located commensurate with theabove statement at one side surface of the parallelepiped block whichdoes not form this corner, i.e. along the diagonal line of thisparallelepiped block at a large distance from the mentioned emissionsurface.

Yet a further object is to provide a generator wherein at least oneelectron-optical control electrode is arranged over the emission cathodewhich is preferably screwed on such that this part which ispredominantly exposed to ion bombardment can easily be exchanged withoutany demounting of further parts of the generator.

Thereby, a desired potential is applied to the control electrode whichelectrode is also used for further purposes, namely to shunt magneticfields over the emission surface of the cathode and, to secure an asgood as possible heat dissipation.

Hence, it is a further object of the invention to provide an electronbeam generator in which the control electrode is designed as a sandwichstructure having a first layer which faces the electrode and amagnetically excellently conducting second layer facing away from thecathode surface, to act in two respects, namely as a heat shield or ionbombardment shield, and as a magnetic shield apart from its possiblecontrol function. In order to increase the heat shield effect thecontrol electrode is structured preferably with an interstice betweenthe layers.

A still further object is to provide a generator having an anode abovethe cathode emission surface which anode is mounted at the contact bodyvia metal connectors whereby the anode to be provided at the emissionside of the cathode is not mounted to the supporting body but rather viaa metal connector at the contact body which as is mentioned above islocated at the side of the cathode facing away from the side of thesupporting body. This guarantees an optimal direct metal heat conductingpath from the anode over the mentioned contact body to the part of theinstallation to which the generator is mounted. Furthermore, the anodeis again demountable without having to change anything at the mountingof the cathode.

A further object is to provide a generator wherein, in order to furtherreduce the influencing of magnetic fields caused by the heating current,an area including a cathode emission surface is separated by a screeningfrom areas having heating current conductors which screening is locatedbetween areas where the heating current conductors extend and the areaof the emission surface of the cathode.

A still further object is to provide a generator which is of a simplestructure and is easy to maintain and wherein the supporting body with acontact body and/or the supporting body with cathode holding blocksand/or the supporting body or one of the cathode holding blocks with thecontrol electrode and/or the cathode holding blocks with the electronemission cathode, are mountable in a form-locked fashion only inpredetermined positions, preferably mountable by screw connectors suchthat all important parts of the generator are mounted with as few screwsas possible and which are designed relative to each other so that theyare mountable in a form-locked manner and against abutments only inpredetermined positions relative to each other. Accordingly, the cathodeholding blocks are mountable at the supporting body only inpredetermined positions and by screws at the cathode holding blocks. Theemission cathode is mounted by screwed clamping members only in apredetermined position. The control electrode, relative to the cathodeemission surface, is also mounted by means of screws and in apredetermined position, as is the anode with a diaphragm for the passingof the electron beam. Fastening by screws is made without a threadedengagement in the supporting body. The parts are screwed together overthe supporting body, and they are clamped relative to each other.

A further object is to provide an electron beam evaporator devicecomprising a beam generator structured as set forth above, which deviceis easy to maintain regarding the electron optical beam generatingmembers and necessitates as few interruptions of the operation aspossible, for maintenance work due to the fact that when maintenancework must be performed on the beam generator, it need not be worked onat the installation but rather can be replaced by a repaired generator.With such a design, not only the vaporizing installation together withsuch generator can be operated with much smaller time spans ofinterruptions of operation, i.e. less down time, but rather the entirevacuum treatment installation has less down time if one considers thatthe electron beam generator is the "heart" of such an installation. Ifthere is a longer stoppage, the installation suffers if no measures aretaken, such as by the inventive generator, to reduce such stoppage andits duration to a minimum. In accordance with the invention an extremelyeasy exchangeability of the parts most subject to wear, such as theanode and control electrode or cathode, or even the entire generator, ismade possible.

BRIEF DESCRIPTION CF THE DRAWINGS

In the drawings:

FIG. 1a is a side view of a generator in accordance with the inventionmounted on a schematically shown part of an installation;

FIG. 1b is a sectional view of a quick release device therein;

FIG. 2 is a top view of the inventive generator of FIG. 1a where theanode plate is partly cut away;

FIG. 3 is a sectional view of the inventive generator of FIG. 2 takenalong line III--III of FIG. 2;

FIGS. 4 and 5 are plan views of directly heated electron emissioncathodes for the inventive generator;

FIG. 6a is a sectional view of a cathode according to FIG. 5, takenalong line VI--VI and having a planar design;

FIG. 6b is a view similar to FIG. 6a but with a domed design;

FIG. 7a is a sectional view of an inventive indirectly heated emissioncathode arrangement; and

FIG. 7b is a top plan view of FIG. 7a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventive beam generator shown in FIG. 1a, is assembled around aninsulating supporting or base body 1 having substantially the shape of aparallelepiped and made for instance of aluminum oxide. A metal contactbody or interface block 7 is clamped by means of e.g. four fastenerscrews 5 on one planar side 3 of the base body whereby the planar side 3of the base body 1 is clamped in the same fashion to a planar surface ofthe block 7. The thread for the screws 5 is not located in the base body1, but e.g. in the interface block 7. This guarantees a definedreproducible heat transfer between the base body 1 and the interfaceblock 7. A quick-release clamping bolt 9 projects out from the side ofthe interface block 7 facing away from the base body 1.

An abutment step 11 is formed in the interface block 7. By means of thisabutment step 11 the interface block 7 is mounted to a correspondingabutment on a part of the installation illustrated schematically at 13,for instance, an electron beam control unit for controlling the path ofthe beam and/or for focussing the beam.

The quick release clamping bolt 9 is inserted into a corresponding (notspecifically illustrated) cylinder bore in the installation part 13. Aclamping bore 15 which narrows down conically is arranged radially inthe quick release clamping bolt 9 and extends preferably completelytherethrough. A clamping screw 14 is in turn arranged at theinstallation part 13 such as illustrated in FIG. 1b and projectsradially into the clamping bore 15. The axis A₁₄ of this screw 14 isoffset relative to the axis A₁₅ of the clamping bore 15 in the directionof insertion of the quick release clamping bolt 9 such that due to thescrewing-in P of the conically extending tip of the screw into theclamping bore 15, the block 7 is clamped in the direction F, due to thewedge forces against the planar machined contact surface of theinstallation part 13.

By means of cathode holding screws 17 of which only one is illustratedin FIG. 1a, two cathode terminal supports 19a and 19b having a threadfor the screws 17 are screwed on, at the side of the base body 1 facingaway from the interface block 7. As illustrated in FIG. 2, respectivereceiving grooves 20a and 20b, are formed in the respective cathodeterminal supports 19a and 19b, whereby one of the two grooves, e.g., thegroove 20b, is somewhat broader than the other groove 20a and both runparallel to each other. A stop bolt 22 projects into groove 20b asillustrated in FIG. 2. The two cathode terminal supports 19a and 19b aredesigned, as illustrated in FIG. 1, so that they overhang on all sidesby an edge 18, over the substantially planar side of the base body 1facing away from the interface block 7. Further the two cathode terminalsupports 19a and 19b extend next to each other as illustrated in FIG.1a, and they are separated by a labyrinth gap 24. Accordingly, if seenfrom the side which includes the grooves 20a and 20b where an emissioncathode is mounted, no visual contact with the insulating base body 1exists. In this way, substantially no vaporizing cathode material ormaterial being vaporized by the electron beam for the process candeposit on the insulating base body 1. Thus the life span of its surfaceis substantially increased. A groove 21 shown in FIG. 3, extends aroundthe base body 1. In this way the path of creeping current along the basebody 1 is made to be much longer.

As specifically illustrated in FIG. 2, and in connection with FIG. 3,the respective terminals 32a and 32b of an electron emission cathode 26are inserted into the two cathode terminal grooves 20a and 20b. Oneterminal of the cathode 26 is of a larger width than the other one suchthat the cathode can be inserted into the grooves in only one definedposition and additionally exactly into the desired position due toabutment with stop bolt 22. After the two cathode terminals have beeninserted the cathode 26 is clamped by means of clamping plates 28a and28b via screws 30a and 30b at the corresponding terminal supports 19aand 19b. Such as illustrated in FIG. 3, the base body 1 forms alreadyfor the parts 7, 19 an exact positioning or locating reference by meansof abutment surfaces.

FIGS. 2 and 3 disclose further that the emission cathode 26 is mountedexclusively at its terminals and the electron emission surface 34 isotherwise freely exposed. This allows the electron emission cathode toexpand thermally in all directions without producing mechanical stressesand accordingly distortions thereof.

Preferably electron emission cathodes are used such as illustrated inFIGS. 4 to 7b. According to FIG. 4 a directly heated electron emissioncathode 26 includes a emission body 41 having a planar shape anddefining a substantially circular emission surface 34. A helical slotarrangement in the body 1 includes a first slot 44a extending from thecathode terminal 32a spirally toward the center Z. A second slot 44b islocated beside the first slot 44a and extends spirally toward the centerZ. The integrity of the emission body 41 is provided in the center Z bya bridge portion 46 remaining there such that a bifilar power conductorarrangement I is realized by the two spiral slots 44a and 44b throughwhich, such as indicated by arrows, a heating current is driven. Thewidth of the slots 44a and 44b, is less than the width D of the currentconductor I and the local production of heat and accordingly thedistribution of the emission of electrons along the emission surfacedefined by the emission body 41 can be influenced by a local, continuousor discontinuous changing of the cross-section of the current conductor.Thereby, the width D of the current conductor is preferably larger thanthe thickness of the plate like body 41.

A further preferred embodiment of the directly heated electron emissioncathode 26 used on the electron beam generator 1, is illustrated in FIG.5. Basically, its structure is similar to the structure of the cathodeillustrated in FIG. 4 but includes in its center Z a preferably circularthrough opening 48 for preventing an erosion due to bombardment by ions.

In FIG. 6a a cross-sectional illustration along line VI--VI of FIG. 5through a preferably used flat electron emission cathode 26 is depictedand FIG. 6b is a cross-sectional illustration of a emission electrodewhich is not planar but rather formed into a spatial plane, such as bypressing the initially planar electrode.

FIG. 7 illustrates an indirectly heated cathode which includes a pot 70which is closed at one side by a removable lid 72 acting as electronemission surface. The lid 72 acting as emission surface is made of thedesired cathode material, possibly different from that of the otherparts of the pot 70. A heating spiral 74 having power supply lines 76and 78, is located in the pot 70 directly adjacent the lid. The powersupply line 76 is connected galvanically to the lid 72 so as to placethe emission surface at the cathode potential. The second power supplyline 78 is insulated and led for instance by means of a ceramic bushing80 out of the pot 70. In order to secure an excellent heat conductingeffect between the heating spiral 74 and the emission surface 72, thepot 70 is structured to be hermetically sealed and has a heat conductinggas encapsulated therein. This is particularly needed in vacuuminstallations. The indirectly heated electrode illustrated schematicallyin FIG. 7 is mounted to the inventive beam generator exactly as thepreviously described, directly heated cathode.

Returning to FIGS. 1a-3, in order to supply heating current I, powersupply bars 51a and 51b, are screwed onto the cathode terminal supports,and specifically regarding the cathode terminal supports 19a and 19b,perpendicularly to the grooves 20a and 20b and at the side of thegenerator remote from the emission surface of the cathode 26. Sectionsof the power supply bars 51a and 51b which project over the plane E ofthe emission surface 34 (see FIG. 1) of the emission cathode 26 are asfar as possible from the surface 34. The spatial areas with the supplybars 51a and 51b and the emission cathode 26, are separated from eachother by a screening plate 53. Such a screening plate 53 as illustratedin FIGS. 1a and 2 by dash-dotted lines, is mounted to the anodepotential for instance by means of a clamping screw.

Furthermore, as be seen in FIG. 2, a control electrode supporting plate55 is mounted and electrically connected to one of the two cathodeterminal supports 19a or 19b, as illustrated by the support 19b, withsupporting plate 55 operated at the same potential as the electronemission cathode. It is thereby effected that the supporting plate 55contacts only one of the two cathode terminal supports 19a or 19b inorder not to short circuit the heating current by the cathode 26. Arecess 57 is made into the supporting plate 55 in which an easilyreplaceable diaphragm insert 61 is fixed by means of screws 59 in aform-locked manner and thus is galvanically connected thereto and whichforms the control electrode. It is thereby quite simply possible tomount the control electrode, with a corresponding mounting of thesupporting plate 55 or of the insert 61 insulated from the potential ofthe electron emission cathode 26 and to set it to a desired potential.

FIG. 2 illustrates further, together when FIG. 1a, that a spacer block63 is screwed to the interface block 7 and supports an anode plate 65having a diaphragm opening 64 which is centered to the cathode emissionsurface.

All described parts of the inventive beam generator are mountable to thebase body 1 in defined positions in a formlocked manner and are easilyreplaceable by a loosening of screw connections. The control electrodeinsert 61 is easy removable and designed as a part which is subject towear such as mentioned earlier. Specifically the diaphragm insert 61acts as a magnetic screen of the electron emission cathode 26 and as aheat shield.

Additionally, the diaphragm insert 61 is made as a sandwich structure,e.g. of Mo and Fe Co. While the Mo layer acts as protection againstradiation or as a heat shield, the Fe Co layer forms a magnetic "shunt"over the electron emission cathode 26 in order to prevent a magneticstray field influence on the shaping of the beam. Between the two layersa interstice 27 is preferably provided, having the effect of improvingthe effectiveness as a heat shield such as illustrated in FIG. 3.

The spacer 63 takes care of good heat dissipation from the anodedirectly to the interface block 7. The heat dissipation between theinventive beam generator and the installation part 13 proceeds via thecontact surface which is pre-tensioned by the quick release clampingbolt 9.

The described inventive electron beam generator is of a small andcompact structure and is with the illustrated quick release fasteningdevice or another easy disengageable mounting possibility extremelysuitable to be rapidly replaced e.g. for maintenance work without a longshut-down of the installation.

While there are shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto, but may be otherwise variously embodied and practicedwithin the scope of the following claims.

We claim:
 1. An electron beam generator arrangement having a heatedelectron emission cathode, and comprising an electrically insulatingsupporting body which, at one side thereof is adapted for mounting to aninstallation, and at another side thereof is adapted for receipt of theelectron emission cathode, the arrangement including a plurality ofabutment surfaces acting as mechanical position references for at leastsaid electron emission cathode and for at least one additional part ofthe generator arrangement, said supporting body being clamped at the oneside onto a metal contact body over a large surface area of the contactbody and the supporting body.
 2. An electron beam generator arrangementhaving a heated electron emission cathode, and comprising anelectrically insulating supporting body which, at one side thereof isadapted for mounting to an installation, and at another side thereof isadapted for receipt of the electron emission cathode, the arrangementincluding a plurality of abutment surfaces acting as mechanical positionreferences for at least said electron emission cathode and for at leastone additional part of the generator arrangement, the arrangementincluding at least one quick release device for a rapid mounting of thegenerator arrangement, located at the one side of said supporting body,said quick release device comprising at least one projecting bolt havinga radial conical bore, the installation having a receiving bore for saidbolt, a radial clamping screw including a conical tip adapted to bedriven into said bore, whereby the axis of said screw is offset relativeto the axis of the bore in said bolt when the bolt is inserted and priorto a driving in of the screw so as to clamp the generator arrangement atthe installation upon a driving in of the screw via the conical bore atthe bolt.
 3. An electron beam generator arrangement having a heatedelectron emission cathode, and comprising an electrically insulatingsupporting body which, at one side thereof is adapted for mounting to aninstallation, and at another side thereof is adapted for receipt of theelectron emission cathode, the arrangement including a plurality ofabutment surfaces acting as mechanical position references for at leastsaid electron emission cathode and for at least one additional part ofthe generator arrangement, the arrangement including two metal cathodeconnection supporting blocks connected to the supporting body at saidother side thereof.
 4. An electron beam generator arrangement having aheated electron emission cathode, and comprising an electricallyinsulating supporting body which, at one side thereof is adapted formounting to an installation, and at another side thereof is adapted forreceipt of the electron emission cathode, the arrangement including aplurality of abutment surfaces acting as mechanical position referencesfor at least said electron emission cathode and for at least oneadditional part of the generator arrangement, the supporting body beingsubstantially in the shape of a parallelpiped, the cathode having anemission surface located substantially at one corner of a surface ofsaid parallelpiped, and wherein heating power supply lines for thecathode are located at a side surface of said parallelpiped which doesnot form said one corner.
 5. An electron beam generator arrangementhaving a heated electron emission cathode, and comprising anelectrically insulating supporting body which, at one side thereof isadapted for mounting to an installation, and at another side thereof isadapted for receipt of the electron emission cathode, the arrangementincluding a plurality of abutment surfaces acting as mechanical positionreferences for at least said electron emission cathode and for at leastone additional part of the generator arrangement, wherein the supportingbody is mounted to the installation and to the additional part by meansof screwing with threads in the installation and additional part and nothreads being in the supporting body.
 6. The arrangement of claim 1, 2,3, 4 or 5, wherein said supporting body consists of Al₂ O₃.
 7. Thearrangement of claim 1, 2, 3, 4 or 5 in which said electron emissioncathode is a cathode which is heated directly by joulean heat or isheated indirectly.
 8. The arrangement of claim 3, wherein the cathodesupporting blocks overhang the supporting body and are designed toextend over each other in a form complementary state without contactingeach other that if viewed from the other side of the supporting body thesupporting body is completely concealed by the blocks.
 9. Thearrangement of claim 1, 2, 3, 4 or 5, wherein at least oneelectron-optical control electrode is arranged over the emissioncathode.
 10. The arrangement of claim 9, wherein said control electrodeis designed as a sandwich structure having at least one first layerwhich faces the cathode and a magnetically excellently conducting secondlayer facing away from the cathode surface.
 11. The arrangement of claim9, comprising a anode above the cathode said anode being mounted at thecontact body via metal connectors.
 12. The arrangement of claim 1, 2, 3,4 or 5, wherein an area including a cathode emission surface of thecathode is separated by a screening, from areas having heating currentconductors.
 13. The arrangement of claim 1, 2, 3, 4 or 5, wherein thesupporting body includes a recess extending around said supporting bodyfor a creeping current between the two sides of the supporting body. 14.The arrangement according to claim 2, 3, 4, or 5, said supporting bodybeing clamped at the one side onto a metal contact body over a largesurface area of the contact body and the supporting body.
 15. Anarrangement according to claim 1, 3, 4 or 5, including at least onequick release device for a rapid mounting of the generator arrangement,located at the one side of said supporting body.
 16. The arrangement ofclaim 15, wherein said quick release device comprises at least oneprojecting bolt having a radial conical bore, the installation having areceiving bore for said bolt, a radial clamping screw including aconical tip adapted to be driven into said bore, whereby the axis ofsaid screw is off-set relative to the axis of the bore in said bolt whenthe bolt is inserted and prior to a driving in of the screw so as toclamp the generator arrangement at the installation upon a driving in ofthe screw via the conical bore at the bolt.
 17. The arrangement of claim7, wherein said cathode comprises an electrode emission surface with acentral area and a peripheral area and including two supportingterminals projecting from said peripheral area of said emission surfaceon one side of said cathode with response to a diameter of said emissionsurface to allow a free thermal expansion of said emission surface withsaid cathode being supported mechanically at said two terminals.
 18. Thearrangement of claim 3, in which the cathode has two terminals and eachcathode supporting block includes a locating device for one of thecathode terminals.
 19. The arrangement of claim 18, wherein the cathodeterminals and the locating devices are structured differently whereby arespective cathode terminal is insertable in only one of the locatingdevices in order to obtain an error-free inserting of a cathode.
 20. Thearrangement of claim 18, wherein an abutment member is located at atleast one of the locating devices in order to locate the emissioncathode in a predetermined position.
 21. The arrangement according toclaim 7, having an electron emission cathode being directly heated byjoulean heat, said cathode comprising an emission body, having at leasttwo spaced conductive terminals for applying an electric current throughsaid emission body for heating said emission body by said joulean heatand said emission body having a slit pattern therein, comprising twohelically arranged slits running substantially one beside the othertoward a central area of said emission body, defining said emissionsurface.
 22. An indirectly heated electron emission cathode arrangementhaving a rigid emission surface and a heating device located at apredetermined distance from the emission surface, in whichthe heatingdevice is a heating current conductor which is heated due to a jouleaneffect; and the rigid emission surface is rigidly connected to theheating current conductor as a structural unit therewith, the emissionsurface being a front surface of a pot in which the heating currentconductor is located, said front surface being exchangeable.
 23. Thearrangement of claim 22, wherein a terminal of the heating currentconductor is galvanically connected to the emission surface.
 24. Thearrangement of claim 22, wherein an encapsulated gas is arranged as heatconducting medium between the heating current conductor and the emissionsurface.